\begin{tikzpicture}[every node/.style={minimum size=1cm,draw}, >=Stealth]
    \coordinate (a) at (0, 0);
    \foreach \text  [count=\i] in {
        输入$x$, $\times 3$, $-1$,  输出$y$
    } {
        \ifnum \i > 1 \relax
            \draw [->] (N.east) -- +(0.5, 0) coordinate (a);
        \fi
        \draw (a) node [right] (N) {\text};
    }
\end{tikzpicture}
% 使用 \graph 的写法见 czds4-ch14-xiti4-1-2
